Large quantities of coal are lost or discarded as useless fines. These fines are generated in various crushing and washing processes. They may also be generated by hydrodesulfurization processes that involve a crushing step prior to chemical treatment. One such process is described in my U.S. Pat. No. 4,127,390 and in my co-pending U.S. application Ser. No. 953,011, filed Oct. 25, 1978 now U.S. Pat. No. 4,183,730.
Hydrodesulfurization processes which relay upon selective reaction with the sulfur ingredients tend to require pulverized coal as a starting ingredient. These processes naturally generate a larger amount of fines than simple washing processes.
Coal fines cannot be transported by conventional means and often allowed to gather unused in large settling basins. These fines are not easily separated from water and even if separated, they cannot be transported in open trucks or cars due to the small particle size. Notwithstanding this drawback, coal fines are a useful energy source and where the fines comprise low sulfur metallurgical quality coal, they are especially desirable for production of coke or for burning in environmentally sensitive locations.
Various prior art methods of treating coal fines to make them suitable for shipment include coating with tar, molasses and similar materials. To applicant's knowledge, they have not produced a strong enough pellet for shipping and handling with normal coal handling equipment. Water soluble binders are unsuitable as the coal pellets made from fines must be able to withstand weathering at outdoor storage locations.
The invention described herein not only allows recovery of hereto wasted coal fines discarded from traditional coal washing process but allows the economical implementations of certain hydrodesulfurization processes which generate large quantities of coal fines.